Plant Uptake Research Articles

Study on Factors Influencing the Migration of Heavy Metals from Soil to Vegetables in a Heavy Industry City

A comprehensive investigation into sustainable agriculture and environmental health was conducted in the Baotou region, encompassing analyses of 90 vegetable samples across 12 varieties and their corresponding rhizosphere soil samples. The physical and chemical properties of the soil, along with the content and chemical speciations of heavy metals, were studied. Results indicated that the study area soil is alkaline to strongly alkaline, with significant heterogeneity in the organic carbon and phosphorus contents, affecting the uptake of heavy metals by these vegetables. The balance of Ca, K, Mg, and P is crucial for soil nutrient equilibrium and reducing heavy metal uptake. The heavy metal contents in the twelve vegetables were below the national food contaminant limit values, with notable accumulations of Cd, Zn, Cu, and Hg. There was a curvilinear correlation between the rhizosphere soil and vegetable contents of Cd and Hg, but differences in uptake were observed. Cd, Zn, Cu, and Hg contents in vegetables were significant, correlating curvilinearly with soil heavy metal content. Soil chemical forms influenced bioavailability, with Cd exhibiting the highest bioactivity. Thus, element migration variations in vegetables reflect the combined influence of the soil’s physical and chemical properties, heavy metal content, and chemical forms. This study validates food safety protocols and soil management practices. Results demonstrate key relationships between soil properties, metal behavior, and plant uptake, enabling targeted solutions for heavy metal contamination and soil remediation. Findings advance sustainable agriculture while protecting ecosystems and food security.

Heavy metal phytoremediation potential of Cosmos bipinnatus for use in chromium-contaminated regions of Dravyavati River, Jaipur, Rajasthan, India.

Due to their toxicity and permanence, heavy metals pose a significant threat as pollutants. Metals leach into soil from human activities including mining, manufacturing, and farming. Phytoremediation involves removing contaminants from soils using herbaceous plants and trees; it is a cost-effective, non-invasive, and aesthetically pleasing technique. The current research investigated the phytoremediation capacity of Cosmos bipinnatus in soil that had been polluted with chromium (Cr) along the Dravyavati River in Jaipur. The plant uptake of heavy metals was studied for 20, 40, 60, and 80 days of growth in pot and field experiments using atomic absorption spectrophotometry (AAS) to analyze residual heavy metal concentrations in the plant's shoots and roots. Chromium exhibited variation in total absorption by plants depending on the type of treatment. Using the translocation factor, it was observed that after 80 days in Nala soil 80% + wheat husk 20% (H2), the plant's capacity to absorb Cr was equivalent and considerably higher. Nola soil 80% + wheat husk 20%; H2, and Nala soil 70% + wheat husk 30%; H3 were among the treatments with TFs more than 1; however, the BCF values were all lower than 1. Additionally, root uptake was greater than shoot uptake. Thus, at H3 and H2 treatments, C. bipinnatus was determined to be an efficient phytoextractor for Cr, but at other concentrations, it acted as an excluder.

Efficient Phosphorus capture from treated sanitary wastewater using a waste-derived SiO2@FeOOH composite: Robustness, Ca2+ interactions, and recovery perspectives

Phosphorus uptake and recovery from sanitary wastewater have been considered a promising approach to producing more sustainable fertilizers, in addition to reducing environmental damage caused by the discharge of this nutrient into water streams. In this study, the Phosphorus adsorption/desorption dynamics exhibited by a tailored SiO2@FeOOH adsorbent, produced using quartz sand waste and Fe derived from the acid dissolution of scrap iron, were examined. The adsorbent’s behavior, robustness, and interaction with Ca2+ ions in simulated treated sanitary wastewater were systematically investigated. As a result, the behavior of the adsorbent under controlled conditions was successfully modeled, and relevant interactions between the material and Ca2+ ions were identified under simulated conditions. The performance of the adsorbent was not affected by the presence of nitrate, carbonate, sulfate, ammonium, fluoride, and humic substances in the simulated media. Additionally, the composite can adsorb humic substances and Phosphorus simultaneously, without interfering with its Phosphorus adsorption capacity. In simulated treated wastewater, the adsorption of the nutrient was enhanced in the presence of Ca2+; however, the formation of insoluble Ca/P deposits on the adsorbent surface significantly changed the adsorption dynamics and disturbed the recovery of Phosphorus using the usual alkaline desorption method. The adsorbent exhibited a robust Phosphorus adsorption capacity as high as 40 mg P/g in simulated treated wastewater, showing clear potential for Phosphorus uptake in Wastewater Treatment Plants. Based on the experimental evidence, future perspectives on the final disposal of the spent adsorbent were also discussed within a circular economy framework.

Tree species controls over nitrogen and phosphorus cycling in a wet tropical forest

AbstractWet tropical forests play an important role in the global carbon (C) cycle, but given current rates of land‐use change, nitrogen (N) and phosphorus (P) limitation could reduce productivity in regenerating forests in this biome. Whereas the strong controls of climate and parent material over forest recovery are well known, the influence of vegetation can be difficult to determine. We addressed species‐specific differences in plant traits and their relationships to ecosystem properties and processes, relevant to N and P supply to regenerating vegetation in experimental plantations in a single site in lowland wet forest in Costa Rica. Single‐tree species were planted in a randomized block design, such that climate, soil (an Oxisol), and land‐use history were similar for all species. In years 15–25 of the experiment, we measured traits regarding N and P acquisition and use in four native, broad‐leaved, evergreen tree species, including differential effects on soil pH, in conjunction with biomass and soil stocks and fluxes of N and P. Carbon biomass stocks increased significantly with increasing soil pH (p = 0.0184, previously reported) as did biomass P stocks (p = 0.0011). Despite large soil N pools, biomass P stocks were weakly dependent on traits associated with N acquisition and use (N2 fixation and leaf C:N, p < 0.09). Mass‐balance budgets indicated that soil organic matter (SOM) could supply the N and P accumulated in biomass via the process of SOM mineralization. Secondary soil P pools were weakly correlated with biomass C and P stocks (R = 0.47, p = 0.08) and were large enough to have supplied sufficient P in these rapidly growing plantations, suggesting that alteration of soil pH provided a mechanism for liberation of soil P occluded in organo‐mineral soil complexes and thus supply P for plant uptake. These results highlight the importance of considering species' effect on soil pH for restoration projects in highly weathered soils. This study demonstrates mechanisms by which individual species can alter P availability, and thus productivity and C cycling in regenerating humid tropical forests, and the importance of including traits into global models of element cycling.

Effect of coexisting nutrient divalent cations on cadmium transport in soil-herbal crop systems

Cadmium (Cd) pollution in Chinese herbal medicines poses a serious risk to medication safety. Regulating Cd uptake, transport, and accumulation in plants through ion-ion interactions offers a novel, environmentally sustainable, and practical approach to address this issue. However, the effects and underlying mechanisms of coexisting divalent cations zinc (Zn), magnesium (Mg), and manganese (Mn) on Cd uptake by Ligusticum sinense cv. Chuanxiong (L. chuanxiong) have not been comprehensively studied or well understood. In this study, the application of coexisting these cations (Zn, Mg, Mn) could significantly promote the growth of L. chuanxiong (21.11%–36.04%) and change the mobility of Cd in the soil-crop system. Specifically, adding Zn decreased Cd content in soil and plants by 18.23% and 20.62%, respectively, while Mg increased it by 10.99% and 62.27%. Mn addition, however, had no significant effect. Similar trends in soil enzyme activity were also observed with Zn, Mg, and Mn treatments. Simultaneously, the findings explore how coexisting divalent cations influence plant physiological responses, including photosynthesis and antioxidant capacities, enabling L. chuanxiong to better manage Cd stress. This study underscores the potential of ion-to-ion interactions as an effective approach to mitigate Cd accumulation, offering a practical and sustainable solution for enhancing the safety of Chinese herbal medicines. Additionally, the effects of mixed cation applications on Cd dynamics are complex, shaped by interactions between ion types, dosages, and their specific properties. These insights provide a foundation for developing more effective remediation strategies for Cd-contaminated soils, particularly in the cultivation of medicinal plants.

Mesoporous silica nanoparticles based on a dual environmental response corresponding to temperature and α-amylase for the control of Spodoptera litura

The design and development of stimuli-responsive nanocarriers hold the promise of the smart delivery of pesticides to target organisms. Herein, we successfully prepared mesoporous silica nanoparticles using the self-templating method, which were grafted with both N-isopropylacrylamide (NIPAM) and cyclodextrin (CD) and loaded with indoxacarb (IN) to afford a pesticide release system with a dual-stimulated response of temperature and α-amylase, referred to as IN@MSNs@NIPAM@CD. Physicochemical characterisation revealed the successful preparation of IN@MSNs@NIPAM@CD with 46.30 % indoxacarb loading. The results showed that IN@MSNs@NIPAM@CD was able to release IN rapidly in the environment of high temperature and α-Amylase, with excellent dual-responsive property. The UV resistance evaluation showed that IN@MSNs@NIPAM@CD could effectively improve the photodegradation resistance of indoxacarb. Fluorescent inverted microscope showed that FITC@MSNs@NIPAM@CD has excellent uptake and translocation properties in corn plants. Bioactivity tests showed that at 14 d, IN@MSNs@NIPAM@CD (LC50 = 9.83 mg L−1) exhibited higher insecticidal activity and longer effective duration than IN@EC (LC50 = 14.64 mg L−1). Acute toxicity test revealed that the IN@MSNs@NIPAM@CD nanoparticles were less acutely toxic to earthworms, zebrafish, BEAS-2B cells and MSNs@NIPAM@CD nanocarriers were safe for the growth of corn. Thus, the dual-responsive nano-controlled-release formulation of IN@MSNs@NIPAM@CD can provide an effective way of achieving the precise delivery and reduced use of pesticides.

Identification of cadmium-tolerant plant growth-promoting rhizobacteria and characterization of its Cd-biosorption and strengthening effect on phytoremediation: Development of a new amphibious-biocleaner for Cd-contaminated site

The use of plant growth-promoting rhizobacteria (PGPR) in decontaminating cadmium-contaminated soil and water is a sustainable and eco-friendly approach. This study aimed to isolate a PGPR strain from the rhizosphere soil of Solanum nigrum and evaluate its potential and mechanisms in remediating Cd-contaminated environments. The results showed that the isolated strain, Klebsiella sp. AW2, can tolerate 240 mg/L Cd2+. Batch biosorption experiments indicated that the optimal conditions for PGPR biosorption were a pH of 5.0, a biosorbent dosage of 1.0 g/L, and a Cd2+ concentration of 10 mg/L, resulting in a biosorption rate of 40.99%. Model fitting results revealed that the Cd biosorption process followed a uniform surface monolayer chemisorption mechanism, likely involving complexation with functional groups such as -NH, -OH, and -C=O, according to Fourier transform infrared spectrometer and desorption experiments. Furthermore, pot experiments demonstrated that PGPR application significantly enhanced the phytoremediation efficiency of Cd-contaminated soil, increasing the phytoextraction ratio by 32.41%. This improvement was primarily achieved by promoting S. nigrum growth and facilitating Cd horizontal transfer from rhizosphere soil to plants through influencing the rhizosphere soil physicochemical properties and Cd2+ influx in roots. In addition, the copy number of the 16S rRNA gene of the PGPR revealed that the PGPR was predominantly localized in the rhizosphere soil, directly leading to increased availability of Cd for plant uptake. Overall, these findings indicate that Klebsiella sp. AW2 is a promising biocleaner for Cd-contaminated environments and provide valuable insights into the application of biosorbents in phytoremediation efforts.

Phosphorus dynamics and sustainable agriculture: The role of microbial solubilization and innovations in nutrient management

Phosphorus (P) is an essential element for plant growth, playing a crucial role in various metabolic processes. Despite its importance, phosphorus availability in soils is often restricted due to its tendency to form insoluble complexes, limiting plant uptake. The increasing demand for phosphorus in agriculture, combined with limited global reserves of phosphate rock, has created challenges for sustainable plant production. Additionally, the overuse of chemical phosphorus fertilizers has resulted in environmental degradation, such as eutrophication of water bodies. Increasing agronomic phosphorus (P) efficiency is crucial because of population growth and increased food demand. Hence, microorganisms involved in the P cycle are a promising biotechnological strategy that has gained global interest in recent decades. Microorganisms' solubilization of phosphate rock (PR) is an environmentally sustainable alternative to chemical processing for producing phosphate fertilizers. Phosphorus-solubilizing microorganisms (PSMs), including bacteria and fungi, and their enzymatic processes offer an eco-friendly and sustainable alternative to chemical inputs by converting insoluble phosphorus into forms readily available for plant uptake. Integrating PSMs into agricultural systems presents a promising strategy to reduce dependence on chemical fertilizers, enhance soil health, and contribute to the transition toward more sustainable and resilient agricultural practices. It can be an alternative that reduces the loss of phosphorus in the environment, especially the eutrophication of aquatic systems. This paper explores the challenges of phosphorus availability in agriculture and the potential of microbial phosphorus solubilization as a sustainable alternative to conventional practices.

Silicon uptake and transport mechanisms in plants: processes, applications and challenges in sustainable plant management.

Silicon (Si) is an abundant element in the earth's crustessential for plant growth and development. Recentstudies silicon's potential for improving plant resilience to numerous biotic stressors, notably fungal diseases. This review seeks to offer a comprehensive understanding of the processes and advantages of silicon-induced systemic resistance in plants, with a special focus on its interactions with fungal pathogens. Furthermore, we investigate the effect of silicon on plant physiological and biochemical changes, such as enhanced lignification, strengthening of physical barriers, and activation of antioxidant systems. Additionally, we examine the influence of silicon on microbial populations within the rhizosphere and its effects on mycorrhizal associations. Lastly, we discuss the potential applications and challenges of integrating silicon-based strategies in sustainable plant disease management. This review provides valuable insights into using silicon as a novel approach to enhance plant systemic resistance against fungal pathogens, offering prospects for developing eco-friendly and efficient agricultural practices.

Conservation Agriculture Boosts Soil Health, Wheat Yield, and Nitrogen Use Efficiency After Two Decades of Practice in Semi-Arid Tunisia

Conservation Agriculture Boosts Soil Health, Wheat Yield, and Nitrogen Use Efficiency After Two Decades of Practice in Semi-Arid Tunisia

Uptake, accumulation and gene response of Sb(Ⅴ) in Arabidopsis thaliana

Antimony (Sb) is a toxic pollutant, with Sb(V) being one of its main forms in the environment, but the process and mechanism of plant uptake of Sb(V) remain unclear. To investigate the process of Sb(V) uptake by plants, Arabidopsis thaliana plants were exposed to water culture media supplemented with different Sb(V) concentrations. The distribution, content, and forms of Sb(V) in Arabidopsis roots, and the accumulation and fixation of Sb(V) in Arabidopsis plants were studied. In addition, inhibitor experiments and analyses of gene expression changes were conducted to elucidate the underlying mechanism of its toxicity. Sb(V) entering the roots was mainly adsorbed on the cell wall, and the Sb(V) content in both apoplastic solution and symplastic solution increased with increasing external Sb(V) concentration. Sb(V) concentration in apoplast and symplast were approximately linearly correlated (R2=0.980), indicating low affinity of cells for Sb(V) absorption. Moreover, uncouplers significantly inhibited the entry of Sb(V) into the symplast, suggesting that the transmembrane transport of Sb(V) is energy-consuming. Sb(V) entering the cell could be partially reduced to Sb(III), and significant changes in glutathione metabolism gene expression were detected, indicating the important role of glutathione metabolism in the detoxification of Sb(V). From the perspective of the whole plant, although Sb(V) is absorbed by the roots, it is mainly fixed in the leaves and stems. This study revealed the pattern of Sb(V) uptake by plants and elucidated the mechanism of Sb(V) uptake by plants from the perspectives of kinetics, physiology, and genetics.

Can nanotechnology and genomics innovations trigger agricultural revolution and sustainable development?

At the dawn of new millennium, policy makers and researchers focused on sustainable agricultural growth, aiming for food security and enhanced food quality. Several emerging scientific innovations hold the promise to meet the future challenges. Nanotechnology presents a promising avenue to tackle the diverse challenges in agriculture. By leveraging nanomaterials, including nano fertilizers, pesticides, and sensors, it provides targeted delivery methods, enhancing efficacy in both crop production and protection. This integration of nanotechnology with agriculture introduces innovations like disease diagnostics, improved nutrient uptake in plants, and advanced delivery systems for agrochemicals. These precision-based approaches not only optimize resource utilization but also reduce environmental impact, aligning well with sustainability objectives. Concurrently, genetic innovations, including genome editing and advanced breeding techniques, enable the development of crops with improved yield, resilience, and nutritional content. The emergence of precision gene-editing technologies, exemplified by CRISPR/Cas9, can transform the realm of genetic modification and enabled precise manipulation of plant genomes while avoiding the incorporation of external DNAs. Integration of nanotechnology and genetic innovations in agriculture presents a transformative approach. Leveraging nanoparticles for targeted genetic modifications, nanosensors for early plant health monitoring, and precision nanomaterials for controlled delivery of inputs offers a sustainable pathway towards enhanced crop productivity, resource efficiency, and food safety throughout the agricultural lifecycle. This comprehensive review outlines the pivotal role of nanotechnology in precision agriculture, emphasizing soil health improvement, stress resilience against biotic and abiotic factors, environmental sustainability, and genetic engineering.

The transcription factor Dof3.6/OBP3 regulates iron homeostasis in Arabidopsis.

Iron is an essential element for plants. Iron uptake by plants is highly regulated, but the underlying mechanism is poorly understood. Using a truncated fragment of the iron deficiency-responsive bHLH100 gene promoter, we screened the Arabidopsis transcription factor yeast one-hybrid (Y1H) library and identified the DOF family protein, OBP3, as a crucial component of the iron deficiency-signaling pathway. OBP3 is a transcriptional repressor with a C-terminal activation domain. Its expression is induced by iron deficiency. The transgenic lines that overexpress OBP3 exhibited iron overload and premature leaf necrosis, while the obp3 mutant was less tolerant of iron deficiency. It was discovered that OBP3 directly targets the Ib subgroup of bHLH gene promoters. OBP3 interacts with the bHLH transcription factor ILR3 (IAA-LEUCINE RESISTANT3), and their interaction enhances the DNA-binding ability and transcriptional promoting activity of OBP3, resulting in the positive regulation of iron deficiency-response genes. In addition, the E3 Ligase BRUTUS facilitates 26S proteasome-mediated degradation of OBP3 protein to prevent excessive iron uptake in plants. In conclusion, our research emphasizes the vital role of OBP3 in regulating plant iron homeostasis.

Nutrient Uptake and Soil Nutrient Status as Influenced by Drip Fertigation Levels and Schedules in Broccoli

The experiment was carried out to study the effect of fertigation levels and schedules on growth and yield of broccoli (Brassica oleracea var italica) during the rabi season of 2021-22 involving 4 levels of fertilizer (75, 100 and 125 % RDF) along with one control (100 % RDF) through soil application and three fertigation scheduling (S1, S2 and S3) with three replications. The result of study revealed that higher fertigation of broccoli with balanced nutrition; better water and nutrient utilization gave significantly higher plant growth and yield and good quality of broccoli. In general, pooled mean revealed that application of 125 % RDF with fertigation schedule S2 :15 % NPK at transplanting to plant establishment, 1-10 DAT, 50 % NPK at curd initiation stage,11-35 DAT and 35 % NPK at curd development stage, 36-60 DAT recorded maximum NPK uptake in plant (kg/ha) and available NPK in soil (kg/ha).

Genome-wide identification and expression analysis of ferric reductase oxidase (FRO) genes in Gossypium spp. reveal their crucial role in iron homeostasis under abiotic and biotic stress

Ferric Reductase Oxidase (FRO) genes are pivotal in iron uptake and homeostasis in plants, yet they are not studied in cotton. Here, we identify and analyze 65 FRO homologs (21 GhFRO, 21 GbFRO, 11 GaFRO, 12 GrFRO) across four Gossypium species (G. hirsutum, G. barbadense, G. arboreum, G. raimondii). FRO exhibit conserved ferric reductase activity and conserved domain structures; Ferric_reduct (PF01794), FAD_binding_8 (PF08022), and NAD_binding_6 (PF08030) across species. Physicochemical properties and subcellular localization analysis provided insights into FRO proteins' functional characteristics, mainly localized to the plasma membrane. Phylogenetic analysis delineates 11 groups, indicating both conserved and divergent evolutionary patterns. Gene structure analysis unveils varying exon-intron compositions. Chromosomal localization shows distribution across A and D genomes, suggesting evolutionary dynamics. Synteny analysis reveals paralogous and orthologous gene pairs subjected to purifying selection. The cis-regulatory elements analysis implicates diverse regulatory mechanisms. Expression profiling highlights dynamic regulation across developmental stages, abiotic and biotic stress conditions. GhFRO interacts with Ca++-dependent protein kinases-10/28-like (CDPKs10/28-like) and metal transporter Natural resistance-associated macrophage protein 6 (Nramp6) to regulate metal ion transport and iron homeostasis. The three-dimensional protein structure prediction suggests potential ligand-binding sites in FRO proteins. Moreover, qRT-PCR analysis of selected eight GhFROs in leaves treated with stress elicitors, MeJA, SA, NaCl, and PEG for 1h, 2h, 4h, and 6h revealed significant downregulation. Overall, this comprehensive study provides insights into FRO gene diversity, evolution, structure, regulation, and function in cotton, with implications for understanding plant iron homeostasis and stress responses.

Development of evaluation method for radiocesium availability in soil by biomimetic approach.

Applicability of biomimetic approach with simulation of plant uptake for assessment of radiocesium availability in soil was investigated. The soil spiked with 137Cs tracer was contacted with wicking material and copper-substituted prussian blue (Cu-PB), which simulate transpirationally induced mass flow and concentration gradient-induced diffusion of radiocesiumin the soil, respectively. Comparison of the removed 137Cs to the wick and the wick + Cu-PB from the soil during the contact period of 12weeks suggested that the diffusion process has larger contribution than the mass flow process in radiocesium dynamics in root zone. The change of the removed rate of 137Cs from the soil was reflected that its availability decreased with the time elapsing and with subjecting repeated wet-dry treatment. The results suggest that the biomimetic approach can be applicable to the realistic evaluation of the availability of radiocesium in soil.

Navigating Pesticide Residue Accumulation in Arable Soils: Insights for Sustainable Agriculture

Adoption and application of wide range chemicals as pesticides for shielding crop against undesirable weeds, insects and pests has increased the overall agricultural productivity in recent decades. According to reports, pesticides which are exposed to a variety of environmental circumstances over an extended period of time cause many of their derivatives to survive in the environment. Accumulation of these chemicals in ecosystems lead their absorption in non-target creatures, planted crops and arable soils, and therefore, causing serious detrimental environmental hazards and many concerns have been brought to light on a worldwide scale. In fact, there may still be health hazards for people associated with the food chain transportation of these pesticide residual compounds. Pesticide residues absorption, on the other hand, is more difficult to understand. Characteristics of the planted crops, the physicochemical qualities of the pesticides and the ambient factors can all have a significant impact on the pesticide residue uptake process and bioavailable concentrations. In the meanwhile, this article will emphasize on overview of these pesticide residue forms and their fate in agricultural soils, mechanisms and factors hindering plant uptake for essential nutrients. To make reasonable risk forecasts for human health, future research must conduct field-based investigations in natural settings.

Influence of Environmental Factors and Epiphytic Bacteria on Arsenic Accumulation and Biotransformation in Hydrilla verticillata (L.f.) Royle

Submerged aquatic plants have potential applications in the phytoremediation of aquatic environments contaminated with arsenic (As). However, the role of epiphytic bacteria that grow on the surface of plants in As uptake and metabolism in plants has often been overlooked. An orthogonal experimental design with nine treatments, four factors, and three levels was conducted to inspect the effects of nitrogen (N, KNO3, 2, 4, 10 mg/L), phosphorus (P, NaH2PO4·2H2O, 0.02, 0.2, 1 mg/L), pH (6, 7, 9), and arsenate (As(V), Na3AsO4·12H2O, 15, 75, 375 μg/L) on As accumulation and biotransformation in sterilized plants and to further explore the role of epiphytic bacteria in the metabolism of As by Hydrilla verticillata (L.f.) Royle. The results indicate that low N, intermediate P, and intermediate pH were beneficial for As accumulation (117.2 ± 62.2 μg/g DW) in sterilized plants, and epiphytic bacteria exhibited promotion (68%) in plants. High N promoted As absorption and transformation in non-sterilized plants but reduced As absorption in sterilized plants. Epiphytic bacteria in the medium showed significant As(III) oxidation, which was affected by environmental factors. These findings can promote remediation efficiency by regulating environmental factors for the phytoremediation of As-contaminated waters.

Calcium Silicate Application as a Salt Stress Mitigation Strategy for Vegetables in the Salt-affected Soils of Sandy Plains of Kerala, India

Soil salinity inhibits plant growth due to osmotic stress and reduced plant and water uptake. In the Onattukara sandy plains of Kerala, saltwater intrusion is a major problem in several panchayaths near the coastal area. In uplands also, cultivation is not possible due to the salt stress from saltwater intrusion. One of the strategies for removing the inhibitory effect of salt stress on plant growth is the application of beneficial nutrients to the plants. Therefore, a study was carried out to understand the effect of calcium silicate application on mitigating salt stress in vegetables and using tomato as a test crop. A detailed germination study was conducted in laboratory conditions prior to pot culture experiment to find out the critical level of salinity for tomato and two salinity levels 30mM and 40 mM NaCl were selected for the pot culture experiment. For accessing the effect of the various levels of calcium silicate on reducing salt stress in tomato, a pot culture experiment was conducted in Onattukara region (AEU 3) in completely randomized design with ten treatments replicated thrice with varying levels of CaSiO3 from 100 kg ha-1 to 150 kg ha-1. The treatments had a significant effect on all the biometric characteristics and yield attributes of the crop. The highest fruit weight, fruit per plant, and fruit yield were observed in treatment with soil test-based NPK recommendation and 125 kg ha-1 of CaSiO3 applied. It was also observed that the relative water content was higher and the water saturation deficit was lower in this treatment. CaSiO3 application @125 kg ha-1 along with soil test-based recommendation of NPK can be recommended as a salt stress mitigation strategy for boosting vegetable production in the salt-affected soils of sandy plains of Kerala.

Marine and terrestrial contributions to atmospheric deposition fluxes of methylated arsenic species

Arsenic, a toxic element from both anthropogenic and natural sources, reaches surface environments through atmospheric cycling and dry and wet deposition. Biomethylation volatilizes arsenic into the atmosphere and deposition cycles it back to the surface, affecting soil-plant systems. Chemical speciation of deposited arsenic is important for understanding further processing in soils and bioavailability. However, the range of atmospheric transport and source signature of arsenic species remain understudied. Here we report significant levels of methylated arsenic in precipitation, cloud water and aerosols collected under free tropospheric conditions at Pic du Midi Observatory (France) indicating long-range transport, which is crucial for atmospheric budgets. Through chemical analyses and moisture source diagnostics, we identify terrestrial and marine sources for distinct arsenic species. Estimated atmospheric deposition fluxes of methylated arsenic are similar to reported methylation rates in soils, highlighting atmospheric deposition as a significant, overlooked source of potentially bioavailable methylated arsenic species impacting plant uptake in soils.